downsample {RSEIS} | R Documentation |
Interpolate time series at higher sample rate.
Description
Interpolate a times series with a higher/lower sample rate for processes that are sensitive to low samples.
Usage
downsample(sig, dt=0.001, newdt=0.01, PLOT=FALSE )
Arguments
sig |
time series vector |
dt |
sample rate s/sample |
newdt |
New, lower sample rate |
PLOT |
logical, plot both traces, default=FALSE |
Details
Linear interpolation is performed between samples. If the newdt is an integer multiple of the old dt, The samples will not be modified.
Value
time series vector with new sample rate.
Author(s)
Jonathan M. Lees<jonathan.lees@unc.edu>
Examples
data(KH)
sig = KH$JSTR[[1]]
#### reduce samples from 125 (0.008) to 25Hz (0.04)
newdt = KH$dt[1]*5
sig2 = downsample(sig, dt = KH$dt[1], newdt = newdt )
L0 = length(sig)
L1 = length(sig2)
op <- par(no.readonly = TRUE)
par(mfrow=c(2,1) )
plot.ts(ts(sig, deltat=KH$dt[1] ), xlab='s',
ylab='Amplitude', main=paste('Orignal', L0) )
grid()
plot.ts(ts(sig2, deltat=newdt ), xlab='s',
ylab='Amplitude', main=paste('Downsample', L1) )
grid()
par(op)
[Package RSEIS version 4.2-4 Index]